Definition

1. Noun:
   • Extrusive igneous rock solidified near or on the surface of the Earth: "Volcanic rock" is rock formed from magma (lava) that has erupted from a volcano or fissure and cooled quickly on or very near the Earth's surface.

Usage

• "Volcanic rock" is used as a mass noun to describe the general material or as a count noun when referring to specific types or instances.
• It is a geological term used to classify rocks based on their origin and formation process.

Examples

• Noun:
  • The island is composed primarily of dark, porous volcanic rock.
  • Basalt and pumice are common types of volcanic rock.
  • Scientists collected samples of the volcanic rock to analyze its mineral composition.

Advanced Usage

• "Volcanic rock" in geology: Refers specifically to the subset of igneous rocks categorized as extrusive.
  • The study focused on the geochemistry of Cenozoic volcanic rocks in the region.

Variants and Related Words

• Extrusive rock: A direct synonym in geological contexts.
• Igneous rock: The broader category that includes both volcanic (extrusive) and plutonic (intrusive) rocks.
• Lava rock: A common informal term, especially for rocks formed from solidified lava flows.
• Specific types: Basalt, andesite, dacite, rhyolite, pumice, scoria, obsidian, tuff.

Synonyms

• Extrusive rock
• Lava rock (informal)

Related Phrases

• Volcanic ash: Fine particles of volcanic rock and glass created during an eruption.
• Volcanic glass: A type of volcanic rock, like obsidian, that cools so rapidly it forms a non-crystalline glass.

Noun

1. extrusive igneous rock solidified near or on the surface of the Earth